Summary and Info:
makepkg -f
==> Erstelle Paket: pacman 3.5.3-1 (So 26. Jun 10:51:29 CEST 2011) [create package]
==> Empfange Quellen... [receive sources]
-> pacman-3.5.3.tar.gz gefunden
-sf: No such file or directory [<--- GNU only call of ln -sf]
/home/saschakb/dev/yaourt/pacman/src//pacman-3.5.3.tar.gz: File exists

==> FEHLER: An unknown error has occurred. Exiting...


makepkg uses the symbolic link command 'ln' and the install command 'install' in ways, that break the posix compatibility and let become makepkg useless in any other userlands then the GNU userland. Other userlands like Busybox, UCB Heirloom, Plan 9, Goblin, sbase, asmutils can't handle this misbehaviour.

Steps to Reproduce:
makepkg on any other userland breaks at passages with ln or install -D

Some Explanation
any install -Dm644 <path><file> could be splitted into
mkdir -p <path>
install -m644 <file>

The ln command knows to arguments:
The -s option causes ln to create symbolic links.
If the -f option is present, ln tries to create hard links to directories.

At the moment, instead of using makepkg, for other userlands we use unipkg (http://aur.archlinux.org/packages.php?ID=35117) to do the job of manually building packages, but lot's of other package tools, that make usage of makepkg, run just into the same problems.

To get more informations - how other userlands are working on the Linux kernelspace and to see, how they can be used instead of the GNU userland on Archlinux, you can have a look here: http://ubd.tumblr.com/
The oldest message describes a complete installation process.

It would be nice, if you could switch to a posix like handling, but of cause I understand, if you say, that Archlinux will handle only the GNU userland - and will be a GNU/Linux.